This invention relates to a typing head for a line printer.
A conventional typing head for a line printer is shown in FIG. 1. In FIG. 1, numerals 1, 2, 3 and 4 designate leaf springs, permanent magnet, yoke, and demagnetizing coils, respectively. Yoke 3, magnet 2 and coils 4 form a yoke assembly. Leaf springs 1 have fixed ends 1b thereof secured by screws 7 between a clamp plate 6 and a fixture 5 rigidly mounted on yoke 3. Leaf springs 1 also have free ends thereof attracted and flexed by permanent magnet 2. Coils 4 are actuated to cause hammer pins 8 disposed on the free ends of the leaf springs 1 to strike against a suitable paper or the like.
One disadvantage of this prior art, however, is that the typing head must be dimensioned as least as high as the length of the leaf springs 1. This is too high to fabricate a thin type of head. Further, the leaf springs 1 which include the fixed ends 1b are vertically disposed in parallel with each other. Accordingly, the free ends 1a are susceptible to deformation in the typing plane resulting in deterioration in typing quality.
It is an object of the invention to provide a thin head producing high typing quality and not readily deformed by external forces.
For accomplishing this object, the leaf springs are arranged side by side in a line. More specifically, each of the leaf springs extends horizontally with its free and fixed ends in a line to establish the relation of the yoke to the adjacent leaf springs with a fixture disposed therebetween.
According to the invention, the leaf springs are horizontally formed in a line and made thinner. Further, the leaf springs are preferably made by punching a flat spring. The free ends of each leaf spring are surrounded by spring surfaces, thereby being resistant to deformation by external force. Pairs of springs may be formed to extend in opposite horizontal directions from a central portion to reduce the number of fasteners required.